Ammunition time fuse



July 30, 1946. c, ZAPPQNE 2,405fi85 AMMUNITION TIME FUSE Filed April 6,1945 I I H5912.

w INVENTOR TTORNEY Patented July 30, 1946 AMMUNITION TIIVIE FUSE CharlesF. Zappone, Greensburg, Pa., assignor to Paragon Manufacturing Company,New Derry, Pa., a corporation of Pennsylvania Application April 6, 1943,Serial No. 481,989

2 Claims. 1

This invention relates to ammunition and explosive devices and, moreparticularly, to time fuses for hand grenades and the like.

Ammunition fuses of the type indicated may depend upon a powder train todelay explosion of the projectile for a predetermined period. Delaymeans of this nature is simple and economical to manufacture in quantityand may be applied in the fuse with a minimum of skill and effort. thedefects of failure to perform and untimely operation due to a variety ofcauses chief among which are uneven burning or non-ignition of thepowder and premature extinction. Fuses for delaying explosion of handgrenades, for example,

are particularly dangerous if subject to misfires, as described, withthe usual proximity of thrower and target.

An object of this invention is to insure a predetermined time delaybefore the fuse ignites the explosive or gas forming mixture.

Another object of the invention is to simplify the manufacture of suchfuses while improving the igniting characteristics.

Another object of the invention is to accomplish the foregoing purposeswithout renderin it necessary to materially alter the ammunition deviceto which the fuse is applied.

Other objects and advantages will become apparent from the followingdescription taken in used for many years in conjunction with the commontype of hand grenade. Thus the body I0 is provided with the usual offsethousing I2 containing the striker mechanism, designated generally by thereferenc numeral I 4. Although not forming part of this invention, thisstriker mechanism I4 may comprise a coil spring I 6 supported in thehousing l2 on a pin l8 and carrying a striker 20 which is held in safeposition by a safety pin 22 which extends through the walls of thehousing I2 and may be forcibly removed by manual effort applied to aring 24 attached to a projecting end thereof. A lever 26 is looselyanchored at one end by an inturned portion 28 thereon engaging a flange30 on one end of the housing l0 and extends across the housing I2 Powdertrains are, however, subject to 10 into operative engagement with thestriker 20 in its safe position. Upon removal of the safety pin 22 asdescribed, the striker 20 may be maintained in its safe position bymanual pressure applied to the lever 26 against the bias of the coilspring which tends to rotate the striker in counterclockwise direction.When the grenade is thrown, the loose mounting of the lever 26 permitsit to become detached from the grenade under pressure of the coil spring16 which thereupon carries the striker 20 into operating position.

Referring further to the body I 0 which is generally cylindrical inform, a threaded projection 32 is provided thereon for attachment of theusual shell 34 of the hand grenade partly shown in broken lines inFig. 1. Depending from the threaded projection 32 is an elongatedprojection 36, reduced in diameter from the threaded projection 32, andhaving an axial opening 38 extending completely therethrough and forminga junction with an enlarged axial opening 48 in the body [0. The axialopening 38 may have a counterbored portion 39 extending a short distancefrom the end opposite the junction described for a purpose which will beapparent hereinafter. The wall of the enlarged opening 40 is providedwith a plurality, in this instance four, of longitudinal ribs M whichmay be equally spaced around the periphery thereof and extendlongitudinally from the open end of the body In to the junction with theaxial opening 38. Any desired number of ribs may be provided withoutdeparture from the salient features of this invention as will beapparent. The four ribs 4| shown may each project into the opening 40short of the axial opening 38 and serve to reduce the free area withinenlarged opening 40 to more or less rectangular form. It will be noted,however, that the ribs 4| do not project into engagement with each otherbut that a passage remains between adjacent ribs and the free area for apurpose described hereinafter.

As previously indicated, the time fuse of this invention is of thepowder train type and the construction and arrangement of the portionsnow to be described in the fuse body forms the subject matter of thisinvention. Accordingly, a time delay element 42 comprising a tubularportion containing a core 44 of combustible material, such as blackpowder, is provided for insertion in the fuse body H). The delay element42 may conveniently be formed by cutting the desired amount from alength of prefabricated material which can be purchased in coils severalfeet in length on the open market. The tubular 3 portion of the delayelement 42 is preferably of metal, such as brass or lead, and the powdercharge forming the core 44, which is solidly packed therein, may bechosen to giv the required burning time, usually four or five seconds,as desired.

The delay element i2 is preferably a close sliding fit in the fuse bodyI and before assembly therein a small quantity of powder is removed fromone end leaving a tubular end portion which projects into the enlargedopening 40 of the body. This tubular end may be punched or swaged in thebody Hi so that a head 58 comprising a plurality, in this instance, fourprojections are formed thereon extending between the ribs 4! and servingto provide sealing relationship between the element and the body.

The opposite end of the delay element 42 projects from the counterboredend 39 of the body after being secured as described. Preferably, thecore i l of this projecting end portion is countersunk, as at 54, toincrease the surface area of the powder and thus enlarge the flameproduced thereby. A detonator element 46 consisting of a tubular pcrtionof metal or other suitable material containin a core 48 of an explosivepowder. such as tetryl, is mounted in the counterbor ed portion bytelescopic engagement with the projecting end of the delay element. Acapsule mounts the core Q8 and a space 52 is left ween the end of thedelay element and the capsule when the parts are assembled. In thisembodiment the capsule may contain a fulminate charge at, but it will beunderstood that other types of fuses may be made by substituting blackpowder for the fulminate and detonator charges described.

The elongated projection 36 of the body i0 is of suliicient length toextend approximately midway of the telescoped ends of the detonatorelement 45 and the delay element 42 when inserted and secured in thebody, as described. The counterbore as accommodates the end of thedetonator element d6 so that the portion of the elongated projection 36which encloses the telescoped ends may now be crimped or swaged to forma depression 52 in the elongated projection 35 and a correspondingdepression in the telescoped ends of the detonator element 46 and thedelay element 42. In this manner, these elements are held rigidly inposition in the elongated projection 36.

In order to retain the detonator and delay elements in assembledrelation and, more importantly. to provide a seal therebetween, thetelescoped ends of these members may be provided with a plurality ofcorrugations 55 extending circumferentially thereof and which mayconveniently be formed after assembly of these elements by spinning,rolling or swaging. The corrugations 5e are preferably located at somedistance from the end face of the detonator element 45 in order toprovide an unbroken surface on that portion of this element which isinserted the fuse body E9, A primer 54 of any suitable type, which willexplode upon percussion by the striker is mounted in the ribbed opening45 and a sealing member 6% secured in overlying relation thereto. Thecompleted fuse is ready for assembly in the grenade or other device ofwhich it forms a component.

The operation of the fuse occurs upon release of the grenade in actionwhich will permit the striker 20 to contact the rimer 64 through thesealing member 66 with sufiicient force or per- 4 cussion to explode theprimer 64 and ignite the charge 44 of the delay element 42.

Owing to the seal established by the head 58 at the junction of theaxial opening 38 with the enlarged opening 46 in the body I0, there isno opportunity for the explosive charge of the primer 6 3 to by-pass thedelay element 42 and ignite the detonator charge prematurely. Theclosely packed core id of combustible material in the delay element willburn evenly at the predetermined rate and, when it is substantiallyconsumed after four or five seconds or other predetermined period, thefulminate charge iii in capsule 50 will operate to explode the detonatormaterial 48 and the function of the fuse is fulfilled. As is Well-known,the grenade shell 34 may contain an explosive charge which operatesinstantaneously upon explosion of the detonator element 46 to cause therequired damage at the target. In the case of gas grenades the fulminateand detonator charges may be replaced with black powder which willignite and cause release of gaseous medium from the grenade casing.

It will be observed that when the core 44 forming the delay charge issubstantially consumed, there is no opportunity for a backfire from'thenext powder in the train owing to the seal established by thecorrugations 56 in the detonator element 46 and the delay element 42.Thus, the fuse assembly is sealed at the initial and finishing stages ofthe time delay, so that after operation of the primer 6d the combustiblematerial of the delay charge 4 3 must be substantially consumed from theprimer to the detonator before the latter can operate. As a solid chargeof combustible material is utilized for the time delay element,substantially even burning will occur and the redetermined time delay isassured before the explosive mixture in the grenade is ignited.

From the foregoing "it will be apparent to those skilled in the art thatthe standard form of hand grenade fuse is adapted without substantialchange to embody the features of this invention. The solid charge delayelement can readily be produced from standard materials purchasable onthe open market. Desired variations can be made in the length of thetime delay by varying the type of combustible material to give therequired characteristics. Other changes can be made in the arrangementand combination of parts and in the details of construction hereindisclosed within the scope of the appended claims without departing fromthe spirit of the invention.

I claim:

l. A time fuse for a grenade casing comprising in combinatioma hollowbody having the opening therein enlarged at oneend a plurality of spacedribs projecting from the interior wall of said enlarged open end andreducing the free area thereof, a primer supported by said ribs in'saidfree area, a detonator element projecting from said body opposite saidenlarged open end, and a time delay element in said body including atubular portion having one end adjacent said primer and the other endconnected to said detonator element, said tubular portion having aplurality of radial projections formed on said adjacent end andextending between said ribs for sealing said portion to said body. v

2. A time fuse for a grenade casing comprising in combination, a hollowbody having the opening therein enlarged at one end to define a shouldertherein, a plurality of spaced ribs pro- Jecting from the interior wallof said enlarged open end to the margin of said shoulder and reducingthe free area of said end to substantially equal the area of saidopening, a primer supported by said ribs in said free area and spacedfrom said shoulder, a detonator element projecting from said bodyopposite said enlarged open end and being peripherally deformed intofixed relation With said body, and a time delay element in said bodyincluding a tubular portion having one end adjacent said shoulder andthe other peripherally deformed into fixed relation with said detonatorelement, said tubular portion having a plurality of radial projectionsformed on said adjacent end and extending between said ribs for sealingsaid portion to said body.

CHARLES F. ZAPPONE.

